Teaching aid

ABSTRACT

A system for improving a swing has a transmitter coil for creating an electromagnetic field aligned with respect to a desired swing plane of a sporting implement and a plurality of coils for detecting an actual swing plane relative to the desired swing plane.

BACKGROUND

The present invention relates to a teaching aid for use by athletes toimprove their swings, and in particular to a golf swing teaching aid.

A variety of teaching aids are used to improve swings in sports such asgolf, tennis, and baseball. Currently, teaching aids include verbalfeedback, video playback, and mechanical guides—all designed to help aplayer feel the appropriate swing plane. However, none of these aidsprovide real-time feedback during an unencumbered, real swing where theathlete is actually hitting a ball at a target, just as he would underreal game conditions.

In the field of improving swings used by certain athletes, there remainsa need for a teaching aid which provides real-time feedback.

Electromagnetic technology has been used in a wide variety ofapplications. Direction-specific electromagnetic fields are used in suchapplications as proximity sensors, magnetic media read-write, findingand discriminating unexploded ordnance from other buried metallicclutter.

In the unexploded ordnance application, an electromagnetic sensorcomprised of a transmitter coil and a receiver coil are used. Thetransmitter coil emits a time varying electromagnetic field. When thiselectromagnetic field energizes a metal target, it induces secondaryfields, which are sensed with the receiver part of the sensor. Byenergizing the target in different directions, then measuring themagnitude of the induced secondary field in three component axis, one isable to ascertain crude target shape and size estimates. The directionalcontrol and dimensionality of these primary electromagnetic fields areadapted in this invention to be used as a reference to define the properswing plane.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a system forimproving a swing, such as a golf swing, which broadly comprises meansfor transmitting an electromagnetic field aligned with respect to adesired swing plane of a sporting implement and means for detecting anactual swing plane relative to the desired swing plane.

Further in accordance with the present invention, there is provided amethod for improving a swing which broadly comprises the steps ofproviding a sporting implement having a plurality of receiver coils in abutt end; generating an electromagnetic field normal to a desired swingplane for the sporting implement; sensing said electromagnetic fieldusing said receiver coils during an actual swing of said sportingimplement; measuring a signal sensed by an axially aligned one of saidreceiver coils; generating a ratio of the signal sensed by said axiallyaligned one of said receiver coils to a vector sum of signals sensed byremaining ones of said receiver coils; and generating a real-time,variable audio signal if the ratio exceeds a predetermined threshold.

Other details of the teaching aid of the present invention are set forthin the following detailed description and the accompanying drawings,wherein like reference numerals depict like elements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a golf swing;

FIG. 2 is a schematic representation of a sporting implement equippedwith receiving coils;

FIG. 3 illustrates an electromagnetic primary transmitted field;

FIG. 4 illustrates a transmitter coil alignment with a desired swingplane;

FIG. 5 is a schematic representation of a method of using the teachingaid system described herein; and

FIG. 6 is a schematic representation of a sporting implement equippedwith receiving coils on a shaft.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

The present invention uses electromagnetic technology to providereal-time, bio-feedback as an athletic teaching aid. For example, thesystem of the present invention may be used to monitor and improve theswing plane of a golf swing, a tennis stroke, or a batting swing. Forthis application, electromagnetic sensor technology is used to measurethe attitude of the club shaft relative to the desired swing plane.

Referring now to FIG. 1, there is shown a golfer 10 and a typical swingplane 12 for a golf swing. The orientation of the swing plane 12relative to a target 14 is a critical factor in the accuracy of the ballflight. In order to achieve proficiency, a golfer 10 must be able toalign the swing plane 12 properly and consistently. Analysts frequentlycomment that a golfer 12 is getting stuck inside, or is cutting acrosshis/her line. These are references to problems with the swing path, i.e.problems keeping the golf club on the proper swing plane. Problems withthe golfer's actual swing plane are hard to self diagnose because thegolfer's perception of the swing plane may not accurately represent hisactual swing plane.

In adapting electromagnetic technology to measure club angle relative tothe desired swing plane, it has been found that one can ignore secondaryfields and simply use a set of receiver coils to measure therelationship of the golf club to the primary field. Referring now toFIG. 2, there is shown a sporting implement 20 which although shown as agolf club could be a tennis racket, a baseball bat, etc. The sportingimplement 20 has a butt end 22. In accordance with a first embodiment,the teaching aid system of the present invention includes a plurality ofreceiver coils 24, 26, and 28 mounted in the butt end 22 of the sportingimplement 20. The receiver coils 24, 26, and 28 in the butt end 22include three orthogonal coils. The coils 24, 26, and 28 provide a wayto measure the angle of the transmitted electromagnetic field relativeto the sporting implement 20. In the case of a golf swing, this allowsone to measure the attitude of the golf club 20 relative to theelectromagnetic field. By doing this, one is able to use electromagnetictechnology to provide real-time feedback of the angle of the club 20relative to the desired swing path or plane.

While the coils 24, 26 and 28 are shown in FIG. 2 as being in the buttend 22, they may, as shown in FIG. 6, be located within a housing 45 ona shaft 44 of the implement 20.

The teaching aid system of the present invention further includes anelectromagnetic transmitter 30 which generates an electromagnetic fieldthat is normal, i.e. orthogonal, to the desired swing plane 12. Thereceiver coils 24, 26, and 28 mounted at the butt end 22 of the sportingimplement 20 or in the shaft 44 are used to measure the angle of theelectromagnetic field. From this, the orientation of the sportingimplement 20 may be derived relative to this field. Having derived theorientation of the sporting implement 20 relative to the EM field andhence the swing plane, the information can be transmitted to the user inreal-time during the swing.

FIG. 3 illustrates the basic components of the primary electromagneticfield. As a time varying current, i.e. a simple sine wave or morecomplex wave form, is applied to the transmitter coil 30, anelectromagnetic field is generated. The direction and the strength ofthe electromagnetic field will vary with the wave form. Of interest isthe fact that, at any position along the plane of the transmitter coil30, the induced electromagnetic field is orthogonal to the plane of thetransmitter coil 30. As a result, the electromagnetic field need not beparticularly powerful or complex.

In the teaching aid system of the present invention, the plane 32 of thetransmitter coil 30 is aligned with the desired swing plane 12 as shownin FIG. 4. By providing such an arrangement, the longitudinal axis 42 ofthe sporting implement 20 is parallel to the plane 32 of the transmittercoil 30. For example in the case of a golf swing, during a properlyexecuted golf swing, as the club 20 is swung along the plane 12, thelongitudinal axis 42 of the golf club 20 will remain parallel to thetransmitted field.

By mounting the three orthogonal receiver coils 24, 26, and 28 at thebutt end 22 or on the shaft 44 of the sporting implement 20, one canmeasure the strength of the field and the ratio of the field encounteredby each component coil 24, 26, and 28. A first one 24 of the coils iscoaxially aligned with the shaft 44 of the sporting implement 20, i.e.the axis of the coil 24 is pointed down the shaft of the sportingimplement 20. Through all phases of the swing, the coil 24 that iscoaxially aligned with the shaft 44 of the golf club 20 will beminimally coupled to the electromagnetic field as long as the sportingimplement 20 remains parallel to the plane 32 of the coil 30. Thisminimum coupling means that the signal sensed by the coil 24 will be ata minimum, relative to the total sensed field, i.e. the root sum of thefield sensed by each component coil 24, 26, and 28. The ratio of thesignal sensed by the coil 24, relative to the total received field isdirectly proportional to the deviation of the longitudinal axis 42 ofthe sporting implement 20 from the desired swing plane 12.

Information about the signal sensed by the coil 24 may be relayed to adevice 50 for providing the athlete or golfer 10 with a detection signalthat the swing plane is not what it should be. For example, the device50 may be an audible device which is incorporated into the sportingimplement 20. The information about the signal sensed by the coil 24 maybe transmitted to the device 50 in any suitable manner. The device 50 onthe implement 20 may be comprised of the three coils 24, 26 and 28attached to preamplifiers attached to A/D converters and amicro-processor. The micro-processor may extract the magnitude of thesignal of the transmit frequency using existing mathematical techniques.The micro-processor may also control a small speaker mounted on thedevice or alternately will send the data via wireless technology (e.g.Blue-Tooth) to a nearby device that can store the data and provide avisual display as well as drive the audio output from the device 50. Inthis way, real-time feedback may be provided to the athlete or golfer 10during each unencumbered swing.

The transmitter coil 30 used in the teaching aid system may be circularor rectangular. Further, the transmitter coil 30 may be comprised of awire conductor wrapped in a series of loops or turns and encased inepoxy. A transmitter electronic package 60 attached to the transmittercoil 30 may be a simple wave form generator designed to run a currentthrough the transmitter coil 30 at a predetermined frequency. Themechanical structure of the transmitter coil 30 allows a precisealignment of the transmitter coil 30 and its transmitted field withrelative ease.

There are two alignment variables that must be accounted for—namely,“aim” and “tilt.” The “aim” of the transmitter coil 30 and itselectromagnetic field refers to the direction that the transmitter coil30 and the desired swing plane 12 is aimed. This is the tangent of thedesired swing plane 12 at the point of impact. If the swing plane 12 wasvertical, this would be very easy to set up. The flat plane of thetransmitter coil 30 would point directly at the target. However, becausethe desired swing plane 12 is tilted, a mechanical guide may be used toensure that the plane 32 of the transmitter coil 30 is properly aimed atthe target 14. This guide may also have provision to set the swing planeto be slightly left or right of the target 14 to allow for the golfer'stendency to hit a draw or fade.

The “tilt” refers to the tilt angle of the field that correspondsdirectly to the sporting implement's 20 lie angle, i.e. the angle of theswing plane 12 relative to the vertical. This adjustment may be a manualadjustment that may need to be made for each club.

To obtain the proper tilt angle, one may use two transmitter coils 30,one vertical and one horizontal. The two coils may be used to controlthe tilt angle of the transmitted electromagnetic field.

As discussed hereinbefore, the receiver coils 24, 26, and 28 are locatedin the butt end 22 or on the shaft 44 of the sporting implement 20. Asdiscussed above, the coils 24, 26, and 28 are used to sense the primarytransmitted field. This field may vary considerably in amplitude as thesporting implement passes through the swing arc, e.g. the butt end 22 ofthe sporting implement 20 will have a swing radius of roughly one meter.The ratio of the coil responses will only vary with the angle of thesporting implement 20. The electronics package 60 will measure thetransmitted signal sensed by each of the receiver coils 24, 26, and 28.As before, the coils 24, 26 and 28 are attached to preamplifiersattached to A/D converters and a micro-processor. The micro-processorwill extract the magnitude of the signal of the transmit frequency usingexisting mathematical techniques and compare the sensed signal amplitudeof the coaxial coil 24, i.e. the coil 24 that is coaxial to thelongitudinal axis 42 of the sporting implement 20, to the vector sum ofthe signal amplitude of the two remaining receiver coils 26 and 28. Thiscomparison will take the form of a ratio that will be indicative of theangle of the sporting implement shaft 44 relative to the desired swingplane angle.

An aural tone generated by the device 50 may be used to indicate whenthis ratio exceeds a predetermined threshold. The tone may be present intwo pitches. One pitch may indicate when the club is inside/under thedesired plane. The second pitch may indicate when the club isoutside/over the desired plane. In both cases the volume of the tonewill vary proportionally to the error in swing angle. Alternatively thepitch of the tone may vary proportionally to the error in swing angle.

While the teaching aid has been described in the context of a golf swingteaching aid, it should be apparent that the teaching aid describedherein could be used for other applications. For example, it could beused to improve a tennis stroke or a baseball swing. For suchapplications, the orthogonal receiver coils 24, 26, and 28 could bemounted in the butt end of a tennis racket or a butt end of a baseballbat.

Referring now to FIG. 5, there is shown the method of using the teachingaid. In step 102, there is provided a sporting implement 20, such as agolf club, having three orthogonal receiver coils 24, 26, and 28 in abutt end 22 or the shaft 44. In step 104, an electromagnetic (EM) fieldis generated normal to a desired swing plane 12. In step 106, thereceiver coils 24, 26, and 28 sense the EM field as the user swings thesporting implement 20 in an unrestricted manner from start of the swingto the finish of the swing. In step 108, the signal sensed by thereceiver coil 24 aligned with the shaft 44 of the sporting implement 20is measured. In step 110, a ratio is generated by comparing the signalamplitude of the signal sensed by the receiver coil 24 to a vector sumof the amplitudes of the signals sensed by the receiver coils 26 and 28.In step 112, an aural tone is generated by the device 50 if the ratioexceeds a predetermined threshold.

As can be seen from the foregoing description, the user or athlete 10 isprovided with real-time feedback that his/her actual swing plane is notaligned with a desired swing plane for the sporting implement.

If desired, in a step 114, one could use the signals generated by thereceiver coils 24, 26, and 28 to recreate graphically on a displaydevice such as a TV screen or a computer screen, a depiction of theathlete's actual swing plane vs. a desired swing plane. To do that, onecan save the signals on a storage device associated with a preprogrammedcomputer and later generate a graphical image for the athlete 10.

There has been described herein a teaching aid. While the teaching aidhas been described in the context of a specific embodiment thereof,other unforeseen alternatives, modifications, and variations may becomeapparent to those skilled in the art having read the foregoingdescription. Accordingly, it is intended to embrace those alternatives,modifications, and variations as fall within the broad scope of theappended claims.

1. A system for improving a swing comprising: means for transmitting anelectromagnetic field aligned with respect to a desired swing plane of asporting implement; and means for detecting an actual swing planerelative to said desired swing plane.
 2. The system of claim 1, furthercomprising means for transmitting a signal to a user in real-time thatthe actual swing plane differs from the desired swing plane.
 3. Thesystem of claim 2, wherein said transmitting means comprises an auraltone device.
 4. The system of claim 3, wherein said aural tone devicegenerates a tone that increases as an angle of the sporting implementincreases relative to the desired swing plane.
 5. The system of claim 3,wherein said aural tone device generates a first pitch which indicateswhen the sporting implement is inside the desired swing plane and asecond pitch when the sporting implement is outside the desired swingplane.
 6. The system of claim 1, wherein said transmitting meanscomprises a transmitting coil which is aligned with the desired swingplane.
 7. The system of claim 6, wherein said transmitting coil iscircular.
 8. The system of claim 6, wherein said transmitting coil isrectangular.
 9. The system of claim 6, wherein said transmitting coilcomprises a wire conductor wrapped in a series of turns and said wireconductor is encased in epoxy.
 10. The system of claim 1, wherein saidsporting implement has a butt end and a shaft said detecting meanscomprises three orthogonal coils mounted in said butt end or on saidshaft.
 11. The system of claim 10, wherein one of said orthogonal coilsis aligned along a longitudinal axis of said sporting implement so thatan axis of the one coil is pointed down a shaft of said sportingimplement.
 12. The system of claim 11, wherein said one coil isminimally coupled to said electromagnetic field when the sportingimplement remains parallel to a plane of said means for generating saidelectromagnetic field.
 13. The system of claim 11, further comprisingmeans for determining the ratio of the signal sensed by the one coilrelative a total received field.
 14. The system of claim 10, whereinsaid orthogonal coils are mounted on said shaft.
 15. The system of claim10, wherein said orthogonal coils are mounted in said butt end.
 16. Thesystem of claim 6, wherein said transmitting means comprises anelectronics package attached to said transmitter coil.
 17. The system ofclaim 16, wherein said electronics package comprises a wave formgenerator.
 18. The system of claim 16, wherein said detecting meanscomprises three orthogonal coils and said electronics package measuresthe transmitter signal sensed by each of the coils and compares anamplitude of a signal generated by a first one of said coils having anaxis pointed down a shaft of the sporting implement to a sum of a signalamplitude of a second and third ones of said coils and generates asignal in the form of a ratio indicative of an angle of the shaft of thesporting implement relative to the desired plane angle.
 19. The systemof claim 18, further comprising means for generating an aural sound whensaid ratio exceeds a predetermined threshold.
 20. The system of claim 1,wherein said sporting implement is a golf club.
 21. The system of claim1, wherein said sporting implement is a tennis racket.
 22. The system ofclaim 1, wherein said sporting implement is a baseball bat.
 23. A methodfor improving a swing comprising the steps of: providing a sportingimplement having a plurality of receiver coils in one of a butt end andon a shaft of said implement; generating an electromagnetic field normalto a desired swing plane for the sporting implement; sensing saidelectromagnetic field using said receiver coils during an actual swingof said sporting implement; measuring a signal sensed by an axiallyaligned one of said receiver coils; generating a ratio of the signalsensed by said axially aligned one of said receiver coils to a sum ofsignals sensed by remaining ones of said receiver coils; and generatinga real-time signal if the ratio exceeds a predetermined threshold. 24.The method of claim 23, wherein said sporting implement providing stepcomprises providing a sporting implement having three orthogonalreceiver coils on said shaft.
 25. The method of claim 23, wherein saidelectromagnetic field generating step comprises providing a transmittercoil aligned with the desired swing plane and supplying an electricalcurrent to said transmitter coil.
 26. The method of claim 23, whereinsaid real time signal generating step comprises generating an auraltone.
 27. The method of claim 26, wherein said aural tone generatingstep comprises generating a tone having a first pitch which indicatesthat the sporting implement is inside the desired swing plane and a tonehaving a second pitch which indicates that the sporting implement isoutside the desired swing plane.
 28. The method of claim 23, furthercomprising creating a graphical image of a plane of the actual swing vs.the desired swing plane.
 29. The method of claim 23, wherein saidsporting implement providing step comprises providing a sportingimplement having three orthogonal receiver coils in said butt end.